x86 smpboot: Re-enable init_udelay=0 by default on modern CPUs

commit f1ccd249 allowed the cmdline "cpu_init_udelay=" to work
with all values, including the default of 10000.

But in setting the default of 10000, it over-rode the code that sets
the delay 0 on modern processors.

Also, tidy up use of INT/UINT.

Fixes: f1ccd249

 "x86/smpboot: Fix cpu_init_udelay=10000 corner case boot parameter misbehavior"
Reported-by: Shane <shrybman@teksavvy.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: dparsons@brightdsl.net
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/9082eb809ef40dad02db714759c7aaf618c518d4.1448232494.git.len.brown@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>